This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Partial nephrectomy is a common surgical technique in which a solitary renal tumor can be successfully removed while sparing the remainder of the viable kidney. This can be performed laparoscopically or by an open procedure. Despite some of the clear advantages of laparoscopic surgery there are also potential disadvantages, including a greater ischemic time and the inability to perform cold ischemia. The aim of this study is to better characterize the extent of ischemic damage and injury sustained to the kidney during laparoscopic and open partial nephrectomy by evaluating the post-operative change in glomerular filtration rate, using the current gold-standard technique.